In recent years, environmental pollution, air pollution and adverse effects on human bodies caused by fine particles such as PM2.5, which are causative substances of air pollution, have become problems. As a solution of the problems, air cleaners are installed indoors to catch indoor fine particles.
In some conventional air cleaners, a HEPA filter or the like is disposed in an air inlet for catching fine particles. However, as soon as the filter catches coarse dust in air sucked from the air inlet, the filter is clogged, thereby degradation in air-conditioning performance frequently occurs. Therefore, frequent maintenance such as cleaning and replacement is required in order to eliminate the clogging. In some cases, although a charged filter and the like capable of selectively absorbing fine particles may be used so that the clogging is less likely to occur, there is a problem that adhesion of particles other than fine particles to the surface of the charged filter impedes the attraction force generated by charging and obstructs catching of fine particles.
Thus, techniques to solve the above problems have been proposed (for example, see Patent Literature 1).
In Patent Literature 1, an air cleaner is provided, comprising an air-sending device for circulating air; a filter unit disposed in a circulating flow of the air for catching dust in the air by a vertical dust-catching surface; and a guide path for guiding the air to the filter unit, wherein following the guide path, a rapid-turning part for the air flow and a coarse dust-accumulating part for receiving coarse dust separated from the air flow that has been turned rapidly are provided.
According to the air cleaner described in Patent Literature 1, since the air cleaner has a separation mechanism by which an air flow is rapidly turned to separate fine dust (fine particles) and coarse dust, sufficient performance to catch coarse dust in air can be obtained. In addition, since the air cleaner does not continue to circulate air like a cyclone device, it has low noise level and is suitable for indoor use.